This section provides background information related to the present disclosure which is not necessarily prior art.
Dynamoelectric machines such as electric motors and generators convert electric energy into mechanical energy, or vice versa.
Electric motors can be classified into two types: single-phase motors and polyphase motors. Single phase motors are driven by a single phase AC power source, whereas polyphase motors are driven by a polyphase AC power source, which is typically a three-phase AC power source. For purposes of this disclosure, a motor driven by a single phase AC power source is a single-phase motor, even if the motor includes multiple windings such as a main winding and an auxiliary/start winding.
Polyphase motors and generators have multiple (typically three) phase windings. Conventionally, the phase windings were formed of copper (including copper alloys). More recently, the phase windings have been formed of aluminum (including aluminum alloys) to reduce the cost of polyphase motors. This is due to the relatively higher cost of copper as compared to aluminum. It is also known to form each phase winding of both copper and aluminum to achieve desired performance characteristics while minimizing the amount of copper used in each phase winding. Again, this is done to reduce the overall cost of the motor, due to the relatively higher cost of copper as compared to aluminum.